The number of cardiac patients dependent on artificial pacing to keep their heart rate at a normal level has been growing rapidly since implantable pacemakers became commercially available. Presently, in the developed countries about a hundred to three hundred patients per one million population join the group of pacemaker wearers each year with an average life expectancy of five years. Thus the number of pacemaker patients may grow in a few years to an absolute value of about 1,250 per one million population (or 275,000 patients in the U.S.A.). The health institutions will be required to provide proper medical care for all of the patients by regular checking of the implanted apparatus.
Special pacemakers clinics have already been established, mostly at the cardiological departments dealing with pacemaker implantations. A common procedure is for the patient to visit the clinic once every three months in the first year after implantation, to keep track of the actual state of the pacing system. Then, as the anticipated lifetime of the pacemaker elapses due to battery exhaustion, the pacemaker function is tested once a month and even more often in order to determine the exact time for its replacement. Presently the most common failure of the pacemakers is exhaustion of the supply battery. However, attentions must also be paid to possible functional defects arising from failing electrical devices and components, from short circuits due to defective technological processes during manufacture, and also to disturbances in delivery of the pacing stimuli and/or in sensing the heart activity due to electrode displacement or breakage.
Special methods have been elaborated for pacemaker evaluation which require sophisticated instrumentation and systems, and professional personnel in cardiology for supervision, carrying out the tests and interpretation of the obtained results. At the present time, the pacemaker check-up arrangements constitute a serious burden for the cardiologists and patients, and their impact will grow steadily with the rise in number of pacemaker patients. The cardiologist has to spend much time on auxiliary routine work, while the patient and his family are burdened both with wasted time and the expenses involved in special visits and travel to pacemaker clinics sometimes located far from home.
In the last few years a trend may be distinguished in the development of pacemaker testing instrumentation: the partial substitution of sophisticated check-up systems by simple, self-contained apparatus. The objective is to allow more frequent pacemaker evaluation in the vicinity of the patient's home or at the home itself. A number of new instrumentation models have already been announced for marketing. However, in principle, they test only one function of the pacemaker, namely the state of the supply battery by counting the pacing rate or by measuring the duraction (width) of the pacing artefact.